ERA17LA280

The flight instructor and commercial pilot's inadequate preflight inspection, which resulted in water contamination of the fuel supply, and a total loss of engine power.

The flight instructor and commercial pilot were conducting an instructional familiarization flight in the light sport airplane; this was the commercial pilots first flight in the airplane under instruction. According to the commercial pilot, they checked the weather and performed a preflight inspection using the checklists. Both fuel tanks were checked and were indicating 1/2 full on the left and slightly more than 1/2 full on the right and no anomalies were noted during the inspection. After departure, they performed several touch-and-go takeoffs and landings and the airplane performed normally but shortly after last takeoff and a climbing left turn to crosswind at 600 ft mean sea level, the engine lost all power and the propeller stopped turning. The instructor took control of the airplane and unsuccessfully attempted a restart; during the restart attempt, the propeller did not move. He performed a forced landing to a field during which the airplane impacted two fences, resulting in the fatal injury to the instructor. Examination of the engine and its components revealed water in the fuel filter, gascolator, fuel pump, and in both carburetors. Additionally, the fuel drained from the right wing tank contained water. Although the No. 2 cylinder bore and piston face exhibited a significant amount of lead build-up, it is likely that the loss of engine power was the result of the extensive water contamination of the fuel system, which should have been detected during the pilots preflight inspection.

The 1055 observation at W96, 1 mile east-northeast of the accident site, included wind from 180° at 5 knots, 10 miles visibility, overcast ceiling at 1,400 ft above ground level, temperature 28°C, dewpoint 26°C, and an altimeter setting of 29.90 inches of mercury. According to Federal Aviation Administration (FAA) airman records, the flight instructor held a commercial pilot certificate with ratings for airplane multiengine land, airplane single-engine land, and instrument airplane; a flight instructor certificate with ratings for airplane single engine and instrument airplane; and a mechanic certificate with powerplant rating. His most recent first-class FAA medical certificate was issued on December 6, 2016, with a limitation for corrective lenses. On the application for that certificate, the pilot reported 4,800 total hours of flight experience with 350 hours in the previous 6 months. The pilot receiving instruction held a commercial pilot certificate with ratings for airplane multiengine land, airplane single-engine land, and instrument airplane. His most recent second-class FAA medical certificate was issued on August 2, 2017, with a limitation for corrective lenses. On the application for that certificate, he reported 256 total hours civilian flight experience. He also reported over 6,050 hours of military flight experience. The airplane impacted a wooden fence just before touchdown, which sheared off one of the landing gear. The airplane slid for about 200 ft after touchdown before striking another wooden fence, which resulted in impact damage to the fuselage, empennage, engine, and wings. The left wing fuel tank was compromised during the impact. The airplane continued another 50 ft, where it came to rest on a gravel road on a magnetic heading of 315°. A section of fence board entered the engine compartment, punctured the firewall and instrument panel, then entered the cockpit . One of the propeller blades was separated and shattered about 14 inches from the hub. The opposing propeller blade was cracked in several locations, but remained intact. The engine was examined at a salvage facility following recovery from the accident site. The engine remained attached to its mounts, which were deformed. Several components, including the number 2 (No. 2 and No. 4 cylinder) carburetor, were found displaced; several wires and hoses, including the fuel return line, were found separated. The exhaust pipes were separated at the muffler. The engine could not be rotated by hand and could not be operated by the starter. The ignition system was examined and was in good physical condition. The spark plugs were removed and examined. The No. 1 cylinder top and bottom spark plugs displayed rust colored material between the insulator nose and inner bore of the thread. The bottom Nos. 1 and 2 spark plugs were filled with a rust-colored liquid. The No. 3 cylinder top and bottom spark plugs exhibited rust between the insulator nose and inner bore of the thread. The bottom No. 3 spark plug was filled with a soapy liquid. The No. 4 top and bottom spark plugs appeared normal in color and in good condition. When compared to the Champion-Aviation Check-a-Plug chart, the spark plugs exhibited signs of significant lead fouling on the Nos. 1, 2, and 3 cylinders. The fuel pump was removed and tested by hand, and produced a liquid consistent with water when the plunger was activated. The fuel return line was found disconnected at its attachment point. No anomalies were found with the fuel lines. The carburetor for cylinder Nos. 1 and 3 and its float bowl were removed and examined. The float bowl contained a liquid consistent with water. The top of the carburetor was disassembled and examined. The rubber diaphragm was found incorrectly installed, as the tab was protruding from the side. The diaphragm was removed and was found to be 180° from its proper location. The carburetor for cylinder Nos. 2 and 4 and its float bowl were removed and examined. The float bowl contained a liquid consistent with water. The main jet was removed and examined for obstruction and proper size. No additional anomalies were found with the carburetor or its components. The airframe fuel lines located forward of the firewall exhibited no anomalies. The gascolator was disassembled and inspected. The internal filter and bowl contained an unknown contaminant that lined the interior surface of the bowl, consistent with corrosion. A clear plastic container was placed under the electric fuel pump to capture any contents. A liquid consistent with water poured out of the fuel pump upon removal. The liquid was tested with water-finding paste, which indicated the presence of water. The fuel filter was removed and found to be partially blocked (30%) with unknown sediment contamination on the filter. The fuel from the right wing tank was drained and placed in a clear plastic container to facilitate examination. A liquid consistent with water was found sitting at the bottom of the container as seen in figure 1. Figure 1. Drained fuel showing water. Removal and examination of the reduction gearbox revealed no anomalies, and the internal gears easily rotated within the gearbox. Rotation of the engine was attempted following removal of the gearbox; however, the engine would not rotate. The No. 2 cylinder head was removed, and examination of the combustion chamber revealed significant combustion residue adhering to the top of the No. 2 piston and the bottom of the No. 2 cylinder, which prevented rotation of the crankshaft. With the No. 2 cylinder head removed, the engine crankshaft could be rotated by hand. Analysis of the spark plug and piston contamination samples revealed that the material was composed of 95% lead, 3% zinc, and 2% bismuth. The airplane was equipped with an Advanced Flight Systems AF-3000 Electronic Flight Information System (EFIS). The memory card was sent to the NTSB Vehicle Recorders Division and read out using laboratory hardware. No accident-related data was found on the memory card. The airplane was a special light sport airplane and received its airworthiness certificate on April 24, 2008. It was a two-place, internally braced, high-wing airplane, with a two-blade fixed pitch propeller that was driven by a Rotax 912 100 horsepower, four-cylinder, four-stroke liquid/air cooled engine. Review of maintenance records indicated that, at the time of the most recent 100-hour inspection on July 10, 2017, the airplane had accumulated 1,164.5 hours total time; the engine had 599.3 hours total time and the tachometer registered 240.4 hours. During the inspection, all cylinder compressions were normal, the oil was changed, and the oil filter was inspected. In addition, the spark plugs were removed, inspected, and reinstalled; there were no discrepancies noted. The previous 100-hour inspection was accomplished on June 15, 2016; the tachometer time and engine total time was 176.5 hours and 535.5 hours, respectively. During the inspection, the spark plugs were replaced and the carburetors were rebuilt. The powertrain section of the airplane maintenance manual detailed interval operating hours. It stated that spark plug inspection was required every 100 hours with replacement every 200 hours unless leaded fuel was used more than 30% of the airplane's operational time, which reduced the replacement interval to 100 hours. It also stated that the engine oil must be drained and replaced every 50 hours, and the oil filter replaced every 50 hours and cut open to examine the filter for contaminants. Airplane records indicated that these maintenance actions were completed as required by the reduced intervals set forth in the maintenance manual The owner of the airplane could not confirm if the operator was using 100LL aviation fuel on a regular basis. He did report that, in May 2017, the operator purchased 25 gallons of 100LL on two separate oc